Physics: CUET Mock Test - 5 - CUET MCQ

Given: E_rms = 300 V
The required equation is → P.I.V. = 2 × E₀ or P.I.V. = 2√2 × E_rms
P.I.V. = 2√2 × 300 V
P.I.V. = 848.52 V ≈ 849 V.

By thin lens formula,
1/f = 1/v - 1/u
1/f = 1/(-50) - 1/(-25)
f = +50 cm.

Original fringe width is given as → β = Dλ/d.
So, the new fringe width is → β’ = 
β’ = 4β
Therefore, the new fringe width is 4 β.

Angular magnification is maximum when the final image is formed at the near point.

u = -7.1 cm.
Therefore, the object should be placed 7.1 cm before the lens to avoid angular magnification.

Fringe width is expressed as:
β = Dλ/d.
So, as the separation (d) between the two slits decreases, the fringe width increases. They are inversely proportional to each other.

Given: I₀ = 0.092 A
The required equation is → I_rms = I_o/√2
I_rms = 0.092/1.414
I_rms = 0.065 A

Given: f = +10 cm; v = -30 cm
Required equations →
1/f = 1/v - 1/u
m = (size of the image/size of the object) = v/u
1/u = 1/v - 1/f = 1/(-30) - 1/10 = 
u = (-15)/2 = -7.5cm
m =v/u = -(30/(-7.5)) = -300/-75 = +4
Therefore, the object should be placed at a distance of 7.5 cm from the lens to get the image at a distance of 30 cm from the lens. It is four times enlarged and is erect.

N = N₀e^{-(λ1 + λ2) t}.
4 = e^{(λ1 + λ2) t}.
t =  = 1080 year.

The sudden increase in current in a Zener diode is due to the rupture of the many covalent bonds present. Therefore, the Zener diode should be connected in reverse bias.

A rectifier is based on the fact that a forward bias p-n junction conducts and a reverse bias p-n junction does not conduct electricity. The rectifier is used to convert alternating current voltage (ac) to direct current voltage (dc).

SiO₂ acts as a diffusion mask permitting selective diffusions into the silicon wafer through the window etched into oxide. In other words, it is used for creating a protective SiO₂ layer on the wafer surface of the IC. Therefore, SiO₂ acts as an insulating component for integrated circuits.

Each of the message signals has different ranges of frequencies. The type of communication system needed for a given signal depends on the bad of frequencies which are considered essential for the communication process.

In Amplitude modulation, the modulating wave is superimposed on a high-frequency carrier wave such that the amplitude of the modulated wave varies as the amplitude of the modulating wave.

Protons are not emitted by radioactive substances during their decay. They are positively charged subatomic particles found in the atomic nucleus. The others can be emitted by radioactive substances during their decay.

Semiconductor diode can be used as a rectifier. The function of a rectifier is that it converts an alternating current into direct current by allowing the current to pass through in one direction.

Rectifier is a device that does the process of rectification. This means that rectifiers straighten the direction of the current flowing through it. There are mainly 2 types of rectifiers, namely, full-wave rectifiers and half-wave rectifiers.

Capacitors are not easy to fabricate on an Integrated Circuit. In fact, they are the most difficult ones to fabricate. This is because capacitors require a lot of attributes such as electromagnetic compatibility, microfabrication techniques, new magnetic materials, etc. and to integrate them, it costs a lot. Therefore, fabricating capacitors is a challenging task.

For speech signals, the frequency range of 300 Hz to 3100 Hz is considered adequate. Therefore, speech signals require a bandwidth of 2800 Hz (3100 Hz – 300 Hz) for commercial telephonic communication.

AGC stands for automatic gain control. Automatic gain control changes (AGC) the overall gain of a receiver automatically so that the strength of the received signal remains almost constant.

In β-emission, a neutron of nucleus decays into a proton and a β-particle.
The reaction given as:
₀n¹ → ₁H² + _-1e⁰.

An oscillator is considered as an amplifier with positive feedback. It converts direct current from a power supply to an alternating current signal. It produces an alternating waveform without any input.

For a half-wave rectifier,

r = 1.21

An Integrated circuit (IC) is an assembly of electronic components, fabricated as a single unit, in which miniaturized active devices and passive devices and their interconnections are built upon a thin substrate of semiconductor material. There are about 600 different types of Integrated circuits.

To transmit music, an approximate bandwidth of 20 kHz is required because of the high frequencies produced by the musical instruments. The audible range of frequencies extends from 20 Hz to 20 kHz.

Amplitude modulation (AM) is used for broadcasting because it avoids receiver complexity. Moreover, only a diode and a capacitor are sufficient to separate the audio signal from the amplitude-modulated wave.

After one half-life, N/2 sample remains and N/2 decays. After two half-lives, N/4 sample remains and N/4 decays out of the remaining N/2 sample. After three half-lives, N/8 sample remains and N/8 sample decays out of the remaining N/4 sample.
So, after three half-lives, in total, N/2 + N/4 + N/8 = 7N/8 decay happens. Hence, the probability that a nucleus undergoes decay after three half-lives is 7/8.

Rectification is the process of conversion of alternating current into direct current. The conversion first powers to alternating current then use a transformer to change the voltage, and finally rectifies power back to direct current.

A magnet can attract another magnet or a magnetic substance like iron. However, a magnet can repel another magnet only. So repulsion is the surer test of magnetism.

Magnetic dipole moment = Pole strength × Magnetic length.
Pole strength = Magnetic dipole moment / Magnetic length
Pole strength = 50.2
Pole strength = 25 Am.